Stretch-spinning device for the manufacture of rayon



May 12, 1959 A. REICHLE ET AL 2,885,729

- STRETCH-SPINNING DEVICE FOR THE MANUFACTURE OF RAYON Filed May 1, 1956 INVENTORSI REICHLE, HANS FROITZHE/M A TTORNEY United States Patent STRETCH-SPINNING DEVICE FOR THE MANUFACTURE OF RAYON Alfred Reichle and Hans Froitzheim, Dormagen, Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany Application May 1, 1956, Serial No. 581,869 Claims priority, application Germany May 3, 1955 3 Claims. (Cl. 18-8) The invention relates to a device for the manufacture of rayon filaments by the stretch-spinning process, particularly by the cupro-ammonium stretch-spinning process, the said device consists of a plurality of spinnerettes arranged to produce separate groups of filaments and corresponding separate funnels arranged in a container, the said funnels being combined together into a common discharge pipe.

In the known spinning process due to the water columns maintained in the multiple funnels, for example double or triple funnels, in the closed system of the spinning head, a very unstable system is set up, and the equilibrium of weight between the separate water columns is disturbed more readily in proportion as the water columns are longer and their volume accordingly greater. During spinning with such devices, the whirling motion of the precipitating liquid due to the diffusion pressure of the ammonia is caused to oscillate, the same being recognized by the fact that the threads, which have been dyed blue by the complex copper salt, pulsate rhythmically over a predetermined path, which pulsation is opposite to the direction of flow and direction of withdrawal of the filaments. The artificial threads spun in this way are unserviceable for further use in normal production.

It has now been found that these disadvantages are avoided according to the invention it the spinning funnels are flared trumpet-fashion at their inlet end and are formed with inlet openings which are disposed perpendicular to the funnel axis and also inclined to the axis of the discharge tube.

The effect hereby obtained is that the precipitant liquid in the funnel system initially flows slowly and then with increasing speed into the common discharge tube, no congestion-'accurring at the joining point of the tunnels. During the coagulation process, the flow velocity of the precipitant liquid is practically equal to the speed of withdrawal of the threads being formed. In this way, undesirable eddy formations within the coagulation path are avoided.

Due to the inclination of the trumpet-shaped funnels to the longitudinal axis of the discharge tube, the precipitant liquid flows down along the inclined wall of these funnels carrying the capillary threads coming out from the spinnerettes along therewith and preventing contact with the funnel wall proper at these inclined portions.

One example of the arrangement according to the invention is shown diagrammatically in the drawing, in which 1 represents the spinning cylinder with the bottom closure plate 2 and the top closure plate 3, on which is arranged the spinning head 4 with the spinnerettes 4a, 4b and 4c. Situated just below these three spinnerettes are the inlet openings 5a, 6a and 7a of the separate funnels 5, 6 and 7, all of which open into a common discharge pipe 8. The precipitant liquid enters the spinning cylinder 1 by way of the passage 9 and flows in the vicinity of the spinnerettes 4a, 4b and 4c into the funnels which are flared trumpetfashion; [the flow of liquid is indicated by arrows]; 10 indicates the supply pipe for the spinning solution into the spinning head 4. The thread being formed flows in the same direction and at approximately the same velocity as the precipitant liquid through the funnels 5, 6 and 7 and the common discharge pipe 8.

The lower part 2 of the spinning cylinder 1 is so designed that the discharge pipe 8 is screwed in or clamped with a nut or locking means; in this way, the spinnerettes and funnels are centered.

Very fine cupro-ammonium rayon threads can be spun with the spinning device which has been described. The assembled bundles of threads can be after-treated, washed or dressed and cut by the conventional methods in such manner that a very fine filamentary cupro-ammonium staple fibre is formed, which is for example spun into yarns in the cotton spinning mills. It is also possible to carry out the treatment of the bundle of threads without the cutting process and to wind the bundles as so-called spinning cables.

We claim:

1. Device for the cupro-ammonium stretch-spinning of rayon filiments comprising means defining a container, a discharge pipe extending through one end portion of said container toward the opposite end, a multiple number of flared spinning funnels branching from said discharge pipe in said container extending in the same direction as said discharge pipe with their longitudinal axes inclined with respect thereto, each of said spinning funnels defining at its free end an inlet opening at substantially right angles to its longitudinal axis, and at least one spinnerette for each of said spinning funnels positioned at the opposed end portion of said container directed at the opening of the spinning funnel associated therewith.

2. Device according to claim 1 in which saiduspinning funnels are flared in the shape of a trumpet end.

3. Devise according to claim 2 which includes three spinning funnels equilaterally disposed about said discharge pipe.

References Cited in the file of this patent UNITED STATES PATENTS 

